Published: 2021-01-15 17:17:33 BdST
Inducing a nick from Marnus Labuschagne that was dropped by his captain Ajinkya Rahane in the gully, Saini then clutched at his inner thigh after completing his follow-through.
Saini complained of pain in his groin and was subsequently taken for scans, a team spokesman said, even though the tourists remain optimistic of his chances of bowling in the match.
"I really wish he comes back and bowls the first over tomorrow," team mate Washington Sundar, who made his Test debut along with left-arm quick T Natarajan at the Gabba, said after the opening day's play.
India had already been forced into four injury changes to the 11 that held Australia to a draw in the third Sydney Test, with bowlers Jasprit Bumrah and Ravichandran Ashwin ruled out along with all-rounder Ravindra Jadeja and batsman Hanuma Vihari.
The series is level at 1-1.